Apple and Google are the biggest competitors in mobile platforms. Now, Google has split off from the Apple-created, open-source WebKit rendering engine behind Apple's Safari browser and Google's Chrome browser, and has created its own open-source version, Blink.

A rendering engine generates a Web page's layout, based on the HTML, CSS and Javascript. Google software engineer Adam Barth, writing on a company blog, said Wednesday that the first step toward creating Blink would be to remove some of the code in WebKit that Blink doesn't need, some 4.5 million lines worth, which he said will improve stability. Google has also issued guidelines for new features in Blink, to foster standards and interoperability.

WebKit has been the most popular engine, powering not only Safari and Chrome but, in various forms, also the default Android browser and the ones for BlackBerry 10 and Symbian devices. Apple released WebKit as open source in 2005, and its versions have grown to cover an estimated 40 percent of the market. Mozilla, maker of Firefox, uses Gecko, and Internet Explorer from Microsoft has Trident.

Opera Is All In

The open-source Chromium project is the basis for both Google's Chrome browser and its Chrome OS. The technology giant has said that, since it employs a different multi-process architecture for Chromium than do other users of WebKit, the back-and-forth to maintain its version and the master underlying open-source engine was slowing innovation.

A few weeks ago, Opera announced that it was moving to WebKit, abandoning its own Presto engine as well as a new engine it had in development. On Thursday, following Google's announcement about Blink, Opera said it was now moving to Blink. The Norway-based browser maker has indicated the latest switch is driven by its interest in supporting Chromium and in getting out of the rendering engine business, so it could focus resources on making new products and features.

These developments are being watched closely in the developer community, although there have been conflicting reactions. When Opera initially said it was going WebKit and dropping its own rendering engine development, for instance, there were complaints that WebKit was becoming the dominant engine because of its wide use, not because of standards, and that this could stifle innovation, especially in the relatively new arena of mobile.

'Already Fragmented'

Now, with Google forking WebKit to create Blink, there is concern that developers will have to support yet another rendering engine, making sure their code renders as intended.

Jeffrey Hammond, an analyst with Forrester, noted that "the reality is that the browser market is already fragmented and is not getting better," with variations across devices and operating systems.

He pointed out that, even with the trend toward using HTML5 standards that should allow apps to play across HTML5-supporting browsers, there will be feature differences in the browsers. The good news, Hammond told us, is that "there's a tremendous amount of innovation." The bad: "there are more edge cases," or exceptions to the norm.

One solution, he said, could be "a good feature-detection library for browsers," so that features in a particular app could be automatically enabled or disabled on specific devices, "depending on what the browser supported."